SANTA ROSA — The parents of a Northern California teen who was fatally shot by a sheriff’s deputy in October have added new allegations to their federal lawsuit against the county.

In a document filed the United States District Court in San Francisco, Rodrigo and Sujey Lopez of Santa Rosa claim that Sonoma County Sheriff’s Deputy Erick Gelhaus had a history of using excessive force.

The lawsuit also claims Gelhaus had racist and extremist tendencies and beliefs.

Gelhaus shot and killed their son, 13-year-old Andy Lopez, on Oct. 22 while the teen was walking home with an airsoft BB gun designed to resemble an assault rifle.

The Santa Rosa Press Democrat reports (http://bit.ly/19ZVqaM) that Gelhaus told investigators he feared for his life because he thought Lopez was armed with an AK-47.